Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to improving resource usage in communication networks using interference cancellation.
Background
Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the Universal Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). Examples of multiple-access network formats include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
A wireless communication network may include a number of base stations or node Bs that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.
A base station may transmit data and control information on the downlink to a UE and/or may receive data and control information on the uplink from the UE. On the downlink, a transmission from the base station may encounter interference due to transmissions from neighbor base stations or from other wireless radio frequency (RF) transmitters. On the uplink, a transmission from the UE may encounter interference from uplink transmissions of other UEs communicating with the neighbor base stations or from other wireless RF transmitters. This interference may degrade performance on both the downlink and uplink.
Some wireless network use a diverse set of base stations, such as higher powered macro cells, and lower powered pico nodes, femto nodes, and relays, to improve the spectral efficiency of the system per unit area. Because these wireless networks use such different base stations and nodes for their spectral coverage, they are often referred to as heterogeneous networks. The higher-powered macro cells are able to offload service of UEs to the lower-powered nodes in order to increase the service capacity and quality. Because the higher power signals from the macro cells may cause interference with the lower power signals from the pico or femto nodes, resource partitioning mechanisms are used to reduce the potential interference. Increased load handling efficiency may be realized by providing service schemes at the edges of the coverage areas of the lower-powered nodes. Within these areas, referred to as the cell range expansion, resource partitioning methods between macro and pico/femto nodes are utilized. However, such partitioning schemas give rise to inefficiencies. For example, when a network is adjusted for greater pico cell range expansion, macro nodes are configured to relinquish resources. Conversely, if no partitioning is implemented, UEs in the pico cell range expansion region will be in outage. To prevent such outage, these UEs connect to the macro node, which results in a disproportionate number of UEs connecting to a macro node instead of a pico/femto node due to the higher power signal of the macro node. These cases each hinder throughput capabilities because of a lack of balance of resources, e.g. when excessive UEs are connected to a pico/femto node, the pico/femto node is forced to maintain the burden for scheduling for each of the UEs. Conversely, when UEs are more directed toward the macro node, the distributed capabilities of the pico/femto nodes are underutilized.
As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.